1. Field of the Invention
The present invention relates generally to an antenna for use on a projectile. More specifically, the present invention relates to a microstrip antenna, designed for use with projectile, which includes a telemetry antenna and a filter for for transmitting to a ground station.
2. Description of the Prior Art
There is currently a need for a microstrip antenna which may used on a projectile to transmit flight performance information for the projectile during a test flight to a ground station or other receiving station. The flight performance information needs to transmitted to the ground or other receiving station to allow for a thorough analysis of flight data and thus insure that the projectile is performing within the performance design criteria for the missile.
There is also a need to insure that the microstrip antenna be light weight and small diameter so that the antenna does not adversely impact the aerodynamic properties of the projectile during a test flight. This insures that telemetry data being transmitted to the ground station accurately reflects the flight performance characteristics of the projectile.
There is also a need for a microstrip antenna which can withstand the G forces exerted on the antenna during a test flight which may cause damage to the antenna or cause the antenna to separate from the projectile. G forces exerted on a microstrip antenna during a test flight of a projectile may be as much as 80,000 G""s
Further, there is a need to insure that antenna operate over the S-Band Frequency range of 2.2-2.3 GHz. In addition, the antenna should include a filter which filters signals outside of the S-Band Frequency range. For example, GPS antennas receive data via RF signals having a center frequency around 1575 MHz. The filter should be designed to filter out these signals.
There is also a need to allow for an adjustment of the bandwidth of the antenna about a center frequency of 2.25 GHz with the adjustment to be up to 50 MHz.
The present invention overcomes some of the disadvantages of the past including those mentioned above in that it comprises a small diameter microstrip antenna which includes a filter integral thereto. The microstrip antenna of the present invention is adapted for use on a projectile where G Forces may reach 80,000 Gs or more. The antenna is a broadband microstrip antenna designed to transmit telemetry data to a ground or other type of receiving station for analysis of the data by the user of the antenna. The antenna is designed to be lightweight so as not to effect the aerodynamic properties of the projectile during a test flight. The antenna is capable of withstanding G forces of up to 80,000 Gs. A first pair of tuning tabs and a second pair of tuning tabs positioned approximately perpendicular to one another allow a user to adjust the bandwidth of the antenna up to 50 MHz about its center frequency of 2.25 GHz.